When you receive these events, their structure members are set as follows.

The type member is set to the event type constant name that uniquely identifies
it. For example, when the X server reports a GraphicsExpose event to a
client application, it sends an XGraphicsExposeEvent structure with the
type member set to GraphicsExpose. The display member is set to a pointer
to the display the event was read on. The send_event member is set to True
if the event came from a SendEvent protocol request. The serial member
is set from the serial number reported in the protocol but expanded from
the 16-bit least-significant bits to a full 32-bit value. The window member
is set to the window that is most useful to toolkit dispatchers.

These structures
have the following common members: window, root, subwindow, time, x, y,
x_root, y_root, state, and same_screen. The window member is set to the
window on which the event was generated and is referred to as the event
window. As long as the conditions previously discussed are met, this is
the window used by the X server to report the event. The root member is
set to the source window's root window. The x_root and y_root members are
set to the pointer's coordinates relative to the root window's origin at
the time of the event.

The same_screen member is set to indicate whether
the event window is on the same screen as the root window and can be either
True or False. If True, the event and root windows are on the same
screen. If False, the event and root windows are not on the same screen.

If the source window is an inferior of the event window, the subwindow
member of the structure is set to the child of the event window that is
the source window or the child of the event window that is an ancestor
of the source window. Otherwise, the X server sets the subwindow member
to None. The time member is set to the time when the event was generated
and is expressed in milliseconds.

If the event window is on the same screen
as the root window, the x and y members are set to the coordinates relative
to the event window's origin. Otherwise, these members are set to zero.

The
state member is set to indicate the logical state of the pointer buttons
and modifier keys just prior to the event, which is the bitwise inclusive
OR of one or more of the button or modifier key masks: Button1Mask, Button2Mask,
Button3Mask, Button4Mask, Button5Mask, ShiftMask, LockMask,
ControlMask, Mod1Mask, Mod2Mask, Mod3Mask, Mod4Mask, and Mod5Mask.

Each of these structures also has a member that indicates the detail.
For the XKeyPressedEvent and XKeyReleasedEvent structures, this member
is called a keycode. It is set to a number that represents a physical key
on the keyboard. The keycode is an arbitrary representation for any key
on the keyboard (see sections 12.7 and 16.1).

For the XButtonPressedEvent
and XButtonReleasedEvent structures, this member is called button. It
represents the pointer button that changed state and can be the Button1,
Button2, Button3, Button4, or Button5 value. For the XPointerMovedEvent
structure, this member is called is_hint. It can be set to NotifyNormal
or NotifyHint.